Helwingia
| Helwingia | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Helwingiaceae | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Helwingia | ||||||||||||
| Willd. nom. cons. |
Helwingia is the only genus ofthe Helwingiaceae family of plants . The distribution area of the only four species extends from the Himalayas to East Asia . The inflorescences lying on the leaves are unusual.
description
Vegetative characteristics
The Helwingia species are evergreen or deciduous shrubs or small trees that usually reach heights of 1 to 2 meters, rarely up to 8 meters. The plants are bare.
The alternate leaves are arranged in a petiole and a leaf blade. The leaf blade is simple. The leaf margin is glandular, serrate or notched. The leaf veins are pinnately branched. The stomata are mainly on the underside of the leaf (abaxial). There are no calcium oxalate crystals in the mesophyll . The "minor leaf veins" (small leaf veins) do not have phloem transfer cells. The two early falling stipules are small and fringed.
Generative characteristics
The flowers sit on the central ribs of the leaves. The inflorescence arises in the leaf axil of its bract. This intergrowth starts with the leaf or inflorescence primordia . Through the action of a basal intercalary meristem, the inflorescence comes to sit on the midrib. The inflorescence is supplied by an additional, adaxially seated bundle of vessels, which arises at the base of the petiole. It is not clear whether this phenomenon can be interpreted as a simple intergrowth of the inflorescence stalk and leaf, or whether another ontogenetic explanation must be used. The Helwingia species are dioeciously separated sexes (diocesan). The inflorescence is a cyme. There are three to four (five) calyx teeth. The three to four (five) petals are green to purple-green. The male flowers are three to 20 in an inflorescence and have three to four (rarely five) stamens in a circle that alternate with the petals. The anthers open with longitudinal slits. The pollen is tri-aperturat and colporat. The female flowers stand alone or up to four in the inflorescence. The stylus is short. Two to four carpels are fused to form a subordinate ovary. There is an incomplete tenuinucellate ovule per carpel . The scar with three to four (rarely five) scar flaps is dry.
The fruit is a stone fruit- like berry with few pips / seeds. The fruit is round, unripe green and turns red to black when ripe. The seed coat (testa) is thin. The endosperm is lightly ruminated; H. The endosperm is furrowed by fold-like tissue growths from the nucellus .
Ingredients and sets of chromosomes
In terms of secondary plant substances , there are flavones , chlorogenic acid and unidentified iridoids . The basic chromosome number is x = 19.
Systematics and distribution
The genus Helwingia was established in 1806 by Carl Ludwig Willdenow : Species Plantarum , 4th edition, volume 2, p. 716. The type species is Helwingia rusciflora Willd. , today a synonym of Helwingia japonica (Thunb.) F.Dietr. var. japonica . The generic name Helwingia honors the East Prussian pastor and botanist Georg Andreas Helwing (1666–1748). The Helwingiaceae family was established by Joseph Decaisne .
The Helwingiaceae are the sister group of the Aquifoliaceae within the order Aquifoliales . The common characteristics are: arched vascular bundle in the petiole, spiral leaves.
The area of the genus extends from the Himalayas to East Asia. The only four species are found in Bhutan , China (all species), northern India , Japan , South Korea , northern Myanmar , Nepal , Sikkim , Thailand and northern Vietnam .
There are four Helwingia species:
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Helwingia chinensis Batalin : There are two varieties:
- Helwingia chinensis Batalin var. Chinensis : It is distributed in northern Myanmar, Thailand and the Chinese provinces of southern Gansu , Guizhou , western Hubei , Hunan , southern Shaanxi , Sichuan and Yunnan .
- Helwingia chinensis var. Crenata (Lingelsh. Ex H.Limpr.) WPCatch : It thrives in mixed forests at altitudes of 1400 to 1900 meters in the Chinese provinces of southeastern Gansu, Guizhou, southern Shaanxi, Sichuan and Yunnan.
- Helwingia himalaica Hook. f. & Thomson ex CBClarke : It is widespread in northern India, Bhutan, Nepal, Sikkim, northern Myanmar, northern Vietnam and China.
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Helwingia japonica (Thunb.) F.Dietr. : There are two subspecies and several varieties:
- Helwingia japonica var. Hypoleuca Hemsl. ex Rehder : It thrives at altitudes of 1200 to 2800 meters in the Chinese provinces of northern Guizhou, western Hubei, southern Shaanxi, Sichuan and northeastern Yunnan.
- Helwingia japonica subsp. japonica : It occurs from Bhutan to China and in southern Korea, southern Japan and Taiwan.
- Helwingia japonica (Thunb.) F.Dietr. var. japonica : Widespread in Bhutan, northern Myanmar, Japan, Taiwan , southern Korea, and China.
- Helwingia japonica subsp. liukiuensis (Hatus.) H.Hara & S.Kuros. (Syn .: Helwingia japonica var. Zhejiangensis (WPFang & TPSoong) MBDeng & Yo.Zhang ): It occurs in Zhejiang and from the Japanese Nansei Islands to Taiwan.
- Helwingia japonica var. Papillosa W.P. Fang & TPSoong : It thrives at altitudes of 2100 to 3400 meters in the Chinese provinces of south-east Gansu, south Shaanxi, north-east and south-west Sichuan.
- Helwingia omeiensis (WPFang) H.Hara & S.Kuros. : It thrives at altitudes of 600 to 1700 meters in the Chinese provinces of southeast Gansu, northern Guangxi , Guizhou, Hubei, Hunan, southern Shaanxi, Sichuan and Yunnan.
No longer belongs to this genus:
- Helwingia argyi H.Lév. & Vaniot is an invalid synonym for Stemona japonica (flower) Miquel , a Stemonaceae .
In the Schmeil-Fitschen system of flowering plants , it is not regarded as an independent family, but rather as belonging to the dogwood family.
Sources and further information
- The Helwingiaceae family at DELTA by L. Watson & MJ Dallwitz (section description)
- The Helwingiaceae family on the AP website . (Sections systematics and description)
- Jenny Qiuyun Xiang & David E. Boufford: Helwingiaceae. , P. 227 - online with the same text as the printed work , In: Wu Zheng-yi, Peter H. Raven, Deyuan Hong (Ed.): Flora of China. Volume 14: Apiaceae through Ericaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 2005, ISBN 1-930723-41-5 . (Sections Description and Systematics)
Individual evidence
- ↑ Timothy A. Dickinson, Rolf Sattler: Development of the Epiphyllous Inflorescence of Helwingia japonica (Helwingiaceae). In: American Journal of Botany , Volume 62, Issue 9, 1975, pp. 962-973 doi : 10.2307 / 2441641 .
- ↑ Lotte Burkhardt: Directory of eponymous plant names . Extended Edition. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2018. [1]
- ↑ a b c d e Rafaël Govaerts (Ed.): Helwingia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved January 10, 2019.
- ↑ a b c d e f g h i Jenny Qiuyun Xiang & David E. Boufford: Helwingiaceae. , P. 227 - online with the same text as the printed work , In: Wu Zheng-yi, Peter H. Raven, Deyuan Hong (Ed.): Flora of China. Volume 14: Apiaceae through Ericaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 2005, ISBN 1-930723-41-5 .
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